The present invention relates to a new cultivation-technological method for the cultivation of tuber-producing plants such as potatoes (Solanum tuberosum L.), jerusalem artichokes (Helianthus tuberosus L.), and the like, having dormant (embryonal) buds in the axils. The method according to the invention, which makes it possible to multiply the production of tubers per unit area, can be applied in the farming as field cultivations, in greenhouse cultivations, etc. The invention also comprises a new device for use in said method.
As is well known tuber-producing plants, especially potatoes, has been cultivated in essentially the same manner for a long time (cp. for example Nordisk Familjebok (1915), Vol. 22, col. 57-58 and B. Svensson "Potatis" 1961, SPOR, p. 37-47). According to this well known method of cultivation seed tubers are set out in rows in a field and then covered with soil. When the plants have emerged a certain distance above the soil surface, the potatoes are usually moulded up, i.e. part of the soil between the rows of potatoes is brought towards the stems of the plants to form a layer of soil sloping downwards from the stems. The moulding up is carried out 1-3 times during the development of the potatoes, the main purpose being to protect the potato tubers from light and thereby prevent green-colouring thereof. As is well known in the art this cultivation method requires a certain minimum distance between the rows of plants and also between the individual plants in each row, which means that the method is area consuming. According to information available from the Central Bureau of Statistics, the average number of potato plants in Sweden is about 4,3 plants per m.sup.2, the number of stems amounting to about 20 per m.sup.2. The number of tubers having a diameter of at least 1 cm amounts to about 60 per m.sup.2. [cp. also G. Rosoi (1975), "Development and structure of spring-sowed crops".] It has been possible to increase the yield per unit area in this cultivation method by means of improved fertilizing methods and the development of new plant varieties, but the increase of the yield has been relatively limited.